SpaceX is sending two private citizens around the moon in 2018

Elon Musk’s aerospace manufacturer and space travel company SpaceX plans to send two tourists around the moon by the end of 2018 — marking the first time that humans have traveled that deep into space in more than 45 years.

Musk — who is perhaps also well known as the co-founder and CEO of electric car company Tesla, and for his new gig on President Trump’s advisory council — refused to say how exactly much the would-be space tourists have paid or name them, although he admitted that they’re not celebrities.

If the private mission takes off as-planned near the end of 2018, it will come 46 years after NASA’s most recent moon landing, in December 1972.

The paying passengers will not step foot on the moon. Instead, they’ll loop around it before sailing back to Earth. In the nearly two years before they take off, the pair will receive extensive training for emergencies, Musk said.

The mission announcement comes about six months after one of SpaceX’s rockets exploded on a Florida launch pad,destroying a commercial satellite that was meant to help bring internet access to Africa. Musk insists that the 2018 trip will be safe, albeit not entirely risk-free.

“They’re certainly not naive, and we’ll do everything we can to minimize that risk, but it’s not zero. But they’re coming into this with their eyes open,” Musk said.

A history of firsts

If the private citizens’ flight goes off as planned, it’ll be another first for the California-based SpaceX — for private citizens to orbit the moon.

SpaceX has worked heavily with NASA since its inception — in 2014, the U.S.’s federal space agencyselected it as one of two private entities to transport NASA astronauts to and from the ISS (Boeing was the other company selected). Those flights likelywon’t take off until 2019.

While the flight around the moon will be a major accomplishment for SpaceX, the billionaire still has his eyes set on Mars. The company’s settlement program, Mars One, aims to establish a permanent human colony on the distant planet.

But the journey to the Red Planet isn’t running on time. SpaceX originally planned to send a robotic probe to Mars in 2018, but that mission wasrescheduled for 2020. SpaceX execs said that they were forced to push back the date to focus on trips to the ISS, and to work with NASA.

The company has been recruiting its frontline of astronaut-pioneers for the program since 2013, when202,586 people applied to be in the first wave of Mars settlers. That pool that has been whittled down to 100. After more cuts this year, 12 to 24 wannabe astronauts will start training, SpaceX said.

Musk’s Mars mission may be humankind’s most tangible hope to get people on the red planet. While NASAhas sent rovers and probes there, it has never attempted to send a human. The government agency has long promised to send astronauts to Mars, although it has never detailed a timeline or plan to do so.

“We think we’re on the right trajectory to get humans to Mars in the 2030’s,” NASA Administrator Charles Boldensaid in April, without providing specifics.

In his inaugural address on Jan. 20, President Donald Trump said the U.S. is “ready to unlock the mysteries of space,” and has sinceurged NASA to fly back to the moon. However, he’s made no mention of Mars.